Slack adjuster for air brakes



June 26, 1956 T. MOORHEAD 2,752,012

SLACK ADJUSTER FOR AIR BRAKES June 26, 1956 T, MOORHEAD 2,752,012

SLACK ADJUSTER FOR AIR BRAKES Filed Feb. 13, 1952 2 Sheets-Sheet 2 H R1 I; SY y 4% 2,752,012 Patented June 26, 1956 2,752,012 SLACK ADJUSTER FOR AIR BRAKES Thomas Moorhead, Atchison,

Locomotive Application February 13, 1952, Serial No. 271,357 1 Claim. (Cl. 18S-198) Kans., assignor to The Finished Material Company, Atchison,

The invention relates to devices for automatic-ally adjusting the slack in the rigging for operating the brake shoes or the clearance between the brake shoes and the car Wheels.

One object of the invention results from Wear on the brake shoes.

Another object of the invention is to provide an improved slack adjusting device which s e'icient in operation and simple in construction.

Other objects of the invention will appear from the detailed description.

The invention consists in the several novel features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a side elevation of an air brake cylinder equipped with a device embodying the invention;

Fig. 2 is a section taken on line 2 2 of Fig. l, the brake operating mechanism and slack adjusting device being shown in normal position;

Fig. 3 is a section taken on line 3 3 of Fig. 2, the brake operating mechanism being shown in brake setting position with the pneumatic slack adjusting device set to take up the slack during the succeeding release of the brakes;

Fig. 4 is a section taken on line 4 4 of Fig. 3;

Fig. 5 is a partial section similar to Fig. 3 showing the auxiliary stem moved outwardly one step for taking up slack; and

Fig. 6 is a side elevation of a portion of the auxiliary stem.

The invention is exemplified with an air brake cylinder 10, a piston 11 slidable in said cylinder and xed to a system, and a spring 14 for retracting its stem.

The invention may be used with brake rigging of standard construction for applying and releasing brake or described in detail.

A thrust sleeve 20 is slidable in the piston stem 13, has an abutment or plug 21 secured in its inner end and is operable by the piston 11 to set the brakes. A hollow auxiliary stem 22 thrust sleeve 20. a bifurcated yoke 23 which is connected by a pin 24 and slots 25 to the distal end of lever 17. A clip 15 secured sleeve 20 extends around a ange 18 of piston stem 13 for retracting sleeve bore of stem 22 to the outer end of on the outer end provided with a series of ratchet teeth 30 and a one-way dog 31 is slidable in a housing 32 which projects from and contains a slidable stem 34 l 20. During each outstroke of piston 11 produced by the delivery of 20 will be operated to set the brakes, the length of the stroke depending piston will insure the setting A pneumatically controlled device for effecting this adjustment comprises: a second series of ratchet teeth 40 on the under side of stem 22 and a one-waydog 41 engaging teeth 40 for latching the stem 22 againstV retraction in the sleeve 20. Dog 41 is slidably mounted in an arm 43, has a stem 44 and is pressed into sliding engagea coil spring 45. An air cylinder step-by-step, relatively to the teeth 40 on stem 22. A spring 52 retracts piston 49 when air is extracted from cylinder 47. A shoulder 51 on piston 49 is adapted to engage the inner end of cylinder 47 for limiting the indog 41. A forked bell crank lever 53 Which is fulcrumed on frame 48 has a pin and 20, and shift slack. Dog 31 will then latch stem 22 to take up the into the second tooth 30 that the succeeding outstrokes said stud and a hand brake operation of the brake wardlyand Operate the brake system to apply the brakes.

When there is no substantial slack. in the brakesystem, the piston strokewill be abouty 8 or normal and no air will flow vi-a pipe'56 to cylinder 47,' and piston 49 will not move in cylinder. 47. Dog 41 will'remain engaged with the rst tooth 40, ,and arm 43 vwill not slide in bracket 48. When there-is a predetermined excess or .increase of slackin the brake system, the stroke ofpiston 11.will be increased proportionately, for example to 81/2, in applying the brakes, and piston 11will permit air to pass fromylinder through pipe 56 into cylinder 47. This airwill impartan inw-ard stroke to/piston 49.and operate ar m43 and dog 41.and said dog Vwill be latched into the second, tooth 40'on stem 22 into position as shown in Fig, 3. During this movement of .dog 41v and pistonA 49, stem 22. will be held against inward movement by dog 31 and the tooth 30. D0g`41 will remain `latched to the secondV tooth 40 on stem 22 whileY the` brakes remain applied. When air under pressure is exhausted from cylindery 10 the brakes will be released and'thestem 22 and sleeve Will-be retracted. Air will also be exhausted from cylinder 47 and spring 52y will shift piston 49, arm 43, `dog 41 and stem 22 into the position shown in Fig. 5. The stem 22 will then sleeve and take up the slack in the brake system so ofV piston 11 of normal length will lapply therbrakes. The dog 31 will latch the second tooth on stem 22 and prevent retraction of said.

stem. Spring 27 holds teeth 30 on stem 22 engaged with dog 31 to prevent retraction of stem 22 in sleeve 20. This adjustment is repeatedeach time the slack is increased a predetermined distance or suiciently to increase the outstrokeof the piston 11 about 1/2 inch, for the operation of piston 49 to latchrinto the next tooth 40 on stem 22, and for cumulativeadjustment ofthe stem 22 in sleeve 2,0 as the 'slack increases. Y

When the-brake shoes have worn to a point requiring replacement, the rings 35 and 54 are manuallyand simultaneously operated to andjdjog41V from ,stem 22.y Stem 22 willthen .be retracted disengage dog 31 from sleeve 20- be shifted outwardly relatively to Cil Y Y Y 4 in said sleeve by spring that dog 31 will engage will engage the first tooth 40 on stem 22.

The invention isfnot to be understood as'restricted to the details set forth, :since these may be modified within the scope of the appended claims without departing from the spirit and scope of the invention.

HavingY thus described'the invention whatlclaim as new and desire to secure by Letters Patent is:

In an air'brake systemfor railway.cars,-the combination with `an air bralrevcylinder, a piston havinga Vtubular stem slidable in the cylinder, a brake-operating lever, aA sleeve in the tubular piston stem, stem slidably mounted Ain-said sleeve for shifting said lever, and av clip connecting the outer end of the piston stern andthe sleeve, for shifting the sleeve with the piston, the piston, sleeve and stem in the sleeve being operable to increase the stroke of th lever upon anv increase, of slack iny the brake system; of

slack adjusting mechanism comprising;- avseries of ratchet in the-sleeve and aspringpressed dog'v teeth onthej stem mounted on the sleeve andfor latching the stem in the sleeve againstinward movement, a second series of ratchet teeth on the. stem, a-secondspring-pressed .dog havinglatching engagementfwith. the second series of teeth, an air cylinder mountedfonthe. sleeve, Va-.pistonslidable in the cylinder on the sleeve, an arm fixed to the lastnamed piston on which the second dog is slidably mounted, for latching lengagement with the second seriesof ratchet teeth, means for delivering airfrom the brake cylinder to the cylinder on slidably shifting the second dog to over-run atooth on said second seriesof teeth, and a spring for shiitingithe second dog to shift tl'i'estem outwardlyY when air is released from the cylinder on the sleeve.y

References Cited in the le of this patent 1 p UNITEDVSTATESy PATENTS 2,648,4(13 l T::II-Aug. 11, 1953 27 into its normal position soV the first tooth 30'and'dog 41* the sleeve upon a predetermined in-V crease of the stroke ofthe piston in the brakecylinder, forv McKee .Feh. 5', 1895 

